Shamusworld >> Repos - rmac/blob - procln.c

   1 //
   2 // RMAC - Reboot's Macro Assembler for the Atari Jaguar Console System
   3 // PROCLN.C - Line Processing
   4 // Copyright (C) 199x Landon Dyer, 2011 Reboot and Friends
   5 // RMAC derived from MADMAC v1.07 Written by Landon Dyer, 1986
   6 // Source Utilised with the Kind Permission of Landon Dyer
   7 //
   8
   9 #include "procln.h"
  10 #include "listing.h"
  11 #include "amode.h"
  12 #include "error.h"
  13 #include "sect.h"
  14 #include "expr.h"
  15 #include "mach.h"
  16 #include "direct.h"
  17 #include "macro.h"
  18 #include "symbol.h"
  19 #include "riscasm.h"
  20
  21 #define DEF_KW                                  // Declare keyword values
  22 #include "kwtab.h"                              // Incl generated keyword tables & defs
  23
  24 #define DEF_MN                                  // Incl 68k keyword definitions
  25 #define DECL_MN                                 // Incl 68k keyword state machine tables
  26 #include "mntab.h"
  27
  28 #define DEF_MR
  29 #define DECL_MR
  30 #include "risckw.h"
  31
  32
  33 IFENT * ifent;                                  // Current ifent
  34 static IFENT ifent0;                    // Root ifent
  35 static IFENT * f_ifent;                 // Freelist of ifents
  36 static int disabled;                    // Assembly conditionally disabled
  37 int just_bss;                                   // 1, ds.b in microprocessor mode
  38 VALUE pcloc;                                    // Value of "PC" at beginning of line
  39 IFENT * ifent;                                  // Current ifent
  40 SYM * lab_sym;                                  // Label on line (or NULL)
  41
  42 const char extra_stuff[] = "extra (unexpected) text found after addressing mode";
  43 const char comma_error[] = "missing comma";
  44 const char syntax_error[] = "syntax error";
  45 const char locgl_error[] = "cannot GLOBL local symbol";
  46 const char lab_ignored[] = "label ignored";
  47
  48 // Table to convert an addressing-mode number to a bitmask.
  49 LONG amsktab[0112] = {
  50         M_DREG, M_DREG, M_DREG, M_DREG,
  51         M_DREG, M_DREG, M_DREG, M_DREG,
  52
  53         M_AREG, M_AREG, M_AREG, M_AREG,
  54         M_AREG, M_AREG, M_AREG, M_AREG,
  55
  56         M_AIND, M_AIND, M_AIND, M_AIND,
  57         M_AIND, M_AIND, M_AIND, M_AIND,
  58
  59         M_APOSTINC, M_APOSTINC, M_APOSTINC, M_APOSTINC,
  60         M_APOSTINC, M_APOSTINC, M_APOSTINC, M_APOSTINC,
  61
  62         M_APREDEC, M_APREDEC, M_APREDEC, M_APREDEC,
  63         M_APREDEC, M_APREDEC, M_APREDEC, M_APREDEC,
  64
  65         M_ADISP, M_ADISP, M_ADISP, M_ADISP,
  66         M_ADISP, M_ADISP, M_ADISP, M_ADISP,
  67
  68         M_AINDEXED, M_AINDEXED, M_AINDEXED, M_AINDEXED,
  69         M_AINDEXED, M_AINDEXED, M_AINDEXED, M_AINDEXED,
  70
  71         M_ABSW,                                                                                 // 070
  72         M_ABSL,                                                                                 // 071
  73         M_PCDISP,                                                                               // 072
  74         M_PCINDEXED,                                                                    // 073
  75         M_IMMED,                                                                                // 074
  76         0L,                                                                                             // 075
  77         0L,                                                                                             // 076
  78         0L,                                                                                             // 077
  79         M_ABASE,                                                                                // 0100
  80         M_MEMPOST,                                                                              // 0101
  81         M_MEMPRE,                                                                               // 0102
  82         M_PCBASE,                                                                               // 0103
  83         M_PCMPOST,                                                                              // 0104
  84         M_PCMPRE,                                                                               // 0105
  85         M_AM_USP,                                                                               // 0106
  86         M_AM_SR,                                                                                // 0107
  87         M_AM_CCR,                                                                               // 0110
  88         M_AM_NONE                                                                               // 0111
  89 };                                                                                                      // 0112 length
  90
  91
  92 //
  93 // Initialize Line Processor
  94 //
  95 void InitLineProcessor(void)
  96 {
  97         disabled = 0;
  98         ifent = &ifent0;
  99         f_ifent = ifent0.if_prev = NULL;
 100         ifent0.if_state = 0;
 101 }
 102
 103
 104 //
 105 // Line Processor
 106 //
 107 void Assemble(void)
 108 {
 109         int state;                                      // Keyword machine state (output)
 110         int j;                                          // Random int, must be fast
 111         char * p;                                       // Random char ptr, must be fast
 112         TOKEN * tk;                                     // First token in line
 113         char * label;                           // Symbol (or NULL)
 114         char * equate;                          // Symbol (or NULL)
 115         int labtyp = 0;                         // Label type (':', DCOLON)
 116         int equtyp = 0;                         // Equ type ('=', DEQUALS)
 117         VALUE eval;                                     // Expression value
 118         WORD eattr;                                     // Expression attributes
 119         SYM * esym;                                     // External symbol involved in expr.
 120         WORD siz = 0;                           // Size suffix to mnem/diretve/macro
 121         LONG amsk0, amsk1;                      // Address-type masks for ea0, ea1
 122         MNTAB * m;                                      // Code generation table pointer
 123         SYM * sy, * sy2;                        // Symbol (temp usage)
 124         char * opname = NULL;           // Name of dirctve/mnemonic/macro
 125         int listflag;                           // 0: Don't call listeol()
 126         int as68mode = 0;                       // 1: Handle multiple labels
 127         WORD rmask;                                     // Register list, for REG
 128         int registerbank;                       // RISC register bank
 129         int riscreg;                            // RISC register
 130         listflag = 0;                           // Initialise listing flag
 131
 132 loop:                                                   // Line processing loop label
 133
 134         // Get another line of tokens
 135         if (TokenizeLine() == TKEOF)
 136         {
 137 if (verb_flag) printf("Assemble: Found TKEOF flag...\n");
 138                 if (list_flag && listflag)                      // Flush last line of source
 139                         listeol();
 140
 141                 if (ifent->if_prev != NULL)                     // Check conditional token
 142                         error("hit EOF without finding matching .endif");
 143
 144                 return;
 145         }
 146
 147         DEBUG DumpTokenBuffer();
 148
 149         if (list_flag)
 150         {
 151                 if (listflag && listing > 0)
 152                         listeol();                                              // Tell listing generator about EOL
 153
 154                 lstout((char)(disabled ? '-' : lntag)); // Prepare new line for listing
 155                 listflag = 1;                                           // OK to call `listeol' now
 156                 just_bss = 0;                                           // Reset just_bss mode
 157         }
 158
 159         state = -3;                                                             // No keyword (just EOL)
 160         label = NULL;                                                   // No label
 161         lab_sym = NULL;                                                 // No (exported) label
 162         equate = NULL;                                                  // No equate
 163         tk = tok;                                                               // Save first token in line
 164         pcloc = (VALUE)sloc;                                    // Set beginning-of-line PC
 165
 166 loop1:                                                                          // Internal line processing loop
 167
 168         if (*tok == EOL)                                                // Restart loop if end-of-line
 169                 goto loop;
 170
 171         // First token MUST be a symbol
 172         if (*tok != SYMBOL)
 173         {
 174 //              error(syntax_error);
 175                 error("syntax error; expected symbol");
 176                 goto loop;
 177         }
 178
 179         j = (int)tok[2];                                                // Skip equates (normal statements)
 180
 181         if (j == '=' || j == DEQUALS || j == SET || j == REG || j == EQUREG || j == CCDEF)
 182         {
 183                 equate = string[tok[1]];
 184                 equtyp = j;
 185                 tok += 3;
 186                 goto normal;
 187         }
 188
 189         // Skip past label (but record it)
 190         if (j == ':' || j == DCOLON)
 191         {
 192 as68label:
 193 //              label = (char *)tok[1];                         // Get label name
 194                 label = string[tok[1]];                         // Get label name
 195                 labtyp = tok[2];                                        // Get label type
 196                 tok += 3;                                                       // Go to next line token
 197
 198                 // Handle multiple labels; if there's another label, go process it,
 199                 // and come back at `as68label' above.
 200                 if (as68_flag)
 201                 {
 202                         as68mode = 0;
 203
 204                         if (*tok == SYMBOL && tok[2] == ':')
 205                         {
 206                                 as68mode = 1;
 207                                 goto do_label;
 208                         }
 209                 }
 210         }
 211
 212         // EOL is legal here...
 213         if (*tok == EOL)
 214                 goto normal;
 215
 216         // Next token MUST be a symbol
 217         if (*tok++ != SYMBOL)
 218         {
 219 //              error(syntax_error);
 220                 error("syntax error; expected symbol");
 221                 goto loop;
 222         }
 223
 224 // This is the problem here: On 64-bit platforms, this cuts the native pointer
 225 // in half. We need to figure out how to fix this.
 226 //#warning "!!! Bad pointer !!!"
 227 #if 0
 228         opname = p = (char *)*tok++;                    // Store opcode name here
 229 #else
 230         opname = p = string[*tok++];
 231 #endif
 232
 233         // Check to see if the SYMBOL is a keyword (a mnemonic or directive).
 234         // On output, `state' will have one of the values:
 235         //    -3          there was no symbol (EOL)
 236         //    -2..-1      the symbol didn't match any keyword
 237         //    0..499      vanilla directives (dc, ds, etc.)
 238         //    500..999    electric directives (macro, rept, etc.)
 239         //    1000..+     mnemonics (move, lsr, etc.)
 240         for(state=0; state>=0;)
 241         {
 242                 j = mnbase[state] + (int)tolowertab[*p];
 243
 244                 // Reject, character doesn't match
 245                 if (mncheck[j] != state)
 246                 {
 247                         state = -1;                                             // No match
 248                         break;
 249                 }
 250
 251                 // Must accept or reject at EOS
 252                 if (!*++p)
 253                 {
 254                         state = mnaccept[j];                    // (-1 on no terminal match)
 255                         break;
 256                 }
 257
 258                 state = mntab[j];
 259         }
 260
 261         // Check for ".b" ".w" ".l" after directive, macro or mnemonic.
 262         siz = SIZN;
 263
 264         if (*tok == DOTW)
 265                 siz = SIZW, tok++;
 266         else if (*tok == DOTL)
 267                 siz = SIZL, tok++;
 268         else if (*tok == DOTB)
 269                 siz = SIZB, tok++;
 270
 271         // Do special directives (500..999) (These must be handled in "real time")
 272         if (state >= 500 && state < 1000)
 273         {
 274                 switch (state)
 275                 {
 276                 case MN_IF:
 277                         d_if ();
 278                 goto loop;
 279                 case MN_ELSE:
 280                         d_else();
 281                         goto loop;
 282                 case MN_ENDIF:
 283                         d_endif ();
 284                         goto loop;
 285                 case MN_IIF:                                            // .iif --- immediate if
 286                         if (disabled || expr(exprbuf, &eval, &eattr, &esym) != OK)
 287                                 goto loop;
 288
 289                         if (!(eattr & DEFINED))
 290                         {
 291                                 error(undef_error);
 292                                 goto loop;
 293                         }
 294
 295                         if (*tok++ != ',')
 296                         {
 297                                 error(comma_error);
 298                                 goto loop;
 299                         }
 300
 301                         if (eval == 0)
 302                                 goto loop;
 303
 304                         goto loop1;
 305                 case MN_MACRO:                                          // .macro --- macro definition
 306                         if (!disabled)
 307                         {
 308                                 if (label != NULL)
 309                                         warn(lab_ignored);
 310
 311                                 DefineMacro();
 312                         }
 313
 314                         goto loop;
 315                 case MN_EXITM:                                          // .exitm --- exit macro
 316                 case MN_ENDM:                                           // .endm --- same as .exitm
 317                         if (!disabled)
 318                         {
 319                                 if (label != NULL)
 320                                         warn(lab_ignored);
 321
 322                                 ExitMacro();
 323                         }
 324
 325                         goto loop;
 326                 case MN_REPT:
 327                         if (!disabled)
 328                         {
 329                                 if (label != NULL)
 330                                         warn(lab_ignored);
 331
 332                                 defrept();
 333                         }
 334
 335                         goto loop;
 336                 case MN_ENDR:
 337                         if (!disabled)
 338                                 error("mis-nested .endr");
 339
 340                         goto loop;
 341                 }
 342         }
 343
 344 normal:
 345         if (disabled)                                                   // Conditionally disabled code
 346                 goto loop;
 347
 348         // Do equates
 349         if (equate != NULL)
 350         {
 351                 // Pick global or local symbol enviroment
 352 #if 0
 353                 j = 0;
 354
 355                 if (*equate == '.')
 356                         j = curenv;
 357 #else
 358                 j = (*equate == '.' ? curenv : 0);
 359 #endif
 360                 sy = lookup(equate, LABEL, j);
 361
 362                 if (sy == NULL)
 363                 {
 364                         sy = NewSymbol(equate, LABEL, j);
 365                         sy->sattr = 0;
 366
 367                         if (equtyp == DEQUALS)
 368                         {
 369                                 // Can't GLOBAL a local symbol
 370                                 if (j)
 371                                 {
 372                                         error(locgl_error);
 373                                         goto loop;
 374                                 }
 375
 376                                 sy->sattr = GLOBAL;
 377                         }
 378                 }
 379                 else if ((sy->sattr & DEFINED) && equtyp != SET)
 380                 {
 381                         if ((equtyp == EQUREG) && (sy->sattre & UNDEF_EQUR))
 382                         {
 383 //REALLY?                               sy->sattre |= ~UNDEF_EQUR;
 384                                 sy->sattre &= ~UNDEF_EQUR;
 385                                 sy->svalue  = 0;
 386                         }
 387                         else if ((equtyp == CCDEF) && (sy->sattre & UNDEF_CC))
 388                         {
 389 //REALLY?                               sy->sattre |= ~UNDEF_CC;
 390                                 sy->sattre &= ~UNDEF_CC;
 391                                 sy->svalue = 0;
 392                         }
 393                         else
 394                         {
 395                                 errors("multiple equate to '%s'", sy->sname);
 396                                 goto loop;
 397                         }
 398                 }
 399
 400                 // Put symbol in "order of definition" list
 401                 if (!(sy->sattr & SDECLLIST))
 402                         sym_decl(sy);
 403
 404                 // Parse value to equate symbol to;
 405                 // o  .equr
 406                 // o  .reg
 407                 // o  everything else
 408                 if (equtyp == EQUREG)
 409                 {
 410 //Linko's request to issue a warning on labels that equated to the same register
 411 //would go here. Not sure how to implement it though. :-/
 412 /*
 413 Maybe like this way:
 414 have an array of bools with 64 entries. Whenever a register is equated, set the
 415 corresponding register bool to true. Whenever it's undef'ed, set it to false. When
 416 checking to see if it's already been equated, issue a warning.
 417 */
 418                         // Check that we are in a RISC section
 419                         if (!rgpu && !rdsp)
 420                         {
 421                                 error(".equr/.regequ must be defined in .gpu/.dsp section");
 422                                 goto loop;
 423                         }
 424
 425                         // Check for register to equate to
 426                         if ((*tok >= KW_R0) && (*tok <= KW_R31))
 427                         {
 428                                 sy->sattre  = EQUATEDREG | RISCSYM;     // Mark as equated register
 429                                 riscreg = (*tok - KW_R0);
 430 //is there any reason to do this, since we're putting this in svalue?
 431 //i'm thinking, no. Let's test that out! :-D
 432 //                              sy->sattre |= (riscreg << 8);           // Store register number
 433 //everything seems to build fine without it... We'll leave it here Just In Case(tm)
 434
 435 #define DEBODGE_REGBANK
 436 #ifdef DEBODGE_REGBANK
 437                                 // Default is current state of "regbank"
 438                                 registerbank = regbank;
 439 #else
 440                                 // Default is no register bank specified
 441                                 registerbank = BANK_N;
 442 #endif
 443
 444                                 // Check for ",<bank #>" override notation
 445                                 if ((tok[1] == ',') && (tok[2] == CONST))
 446                                 {
 447                                         // Advance token pointer to the constant
 448                                         tok += 3;
 449
 450                                         // Anything other than a 0 or a 1 will result in "No Bank"
 451                                         if (*tok == 0)
 452                                                 registerbank = BANK_0;
 453                                         else if (*tok == 1)
 454                                                 registerbank = BANK_1;
 455                                 }
 456
 457 #ifdef DEBODGE_REGBANK
 458                                 sy->sattre |= registerbank;     // Store register bank
 459 #else
 460 // What needs to happen here is to prime registerbank with regbank, then use
 461 // registerbank down below for the bank marking.
 462 #warning "!!! regbank <-> registerbank confusion here !!!"
 463 // The question here is why, if we're allowed to override the ".regbankN" rules above,
 464 // then why is it using the one set by the directive in the extended attributes and
 465 // not in what ends up in symbol->svalue?
 466 // ".regbankN" is not an original Madmac directive, so it's suspect
 467                                 sy->sattre |= regbank;          // Store register bank
 468 #endif
 469                                 eattr = ABS | DEFINED | GLOBAL;
 470 // & what does this $80000080 constant mean???
 471 //                              eval = 0x80000080 + (riscreg) + (registerbank << 8);
 472                                 eval = riscreg;
 473                                 tok++;
 474                         }
 475                         // Checking for a register symbol
 476                         else if (tok[0] == SYMBOL)
 477                         {
 478                                 sy2 = lookup(string[tok[1]], LABEL, j);
 479
 480                                 // Make sure symbol is a valid equreg
 481                                 if (!sy2 || !(sy2->sattre & EQUATEDREG))
 482                                 {
 483                                         error("invalid GPU/DSP .equr/.regequ definition");
 484                                         goto loop;
 485                                 }
 486                                 else
 487                                 {
 488                                         eattr = ABS | DEFINED | GLOBAL; // Copy symbols attributes
 489                                         sy->sattre = sy2->sattre;
 490                                         eval = (sy2->svalue & 0xFFFFF0FF);
 491                                         tok += 2;
 492                                 }
 493                         }
 494                         else
 495                         {
 496                                 error("invalid GPU/DSP .equr/.regequ definition");
 497                                 goto loop;
 498                         }
 499                 }
 500                 else if (equtyp == REG)
 501                 {
 502                         if (reglist(&rmask) < 0)
 503                                 goto loop;
 504
 505                         eval = (VALUE)rmask;
 506                         eattr = ABS | DEFINED;
 507                 }
 508                 else if (equtyp == CCDEF)
 509                 {
 510                         sy->sattre |= EQUATEDCC;
 511                         eattr = ABS | DEFINED | GLOBAL;
 512
 513                         if (tok[0] == SYMBOL)
 514                         {
 515                                 sy2 = lookup(string[tok[1]], LABEL, j);
 516
 517                                 if (!sy2 || !(sy2->sattre & EQUATEDCC))
 518                                 {
 519                                         error("invalid gpu/dsp .ccdef definition");
 520                                         goto loop;
 521                                 }
 522                                 else
 523                                 {
 524                                         eattr = ABS | DEFINED | GLOBAL;
 525                                         sy->sattre = sy2->sattre;
 526                                         eval = sy2->svalue;
 527                                         tok += 2;
 528                                 }
 529                         }
 530                         else if (expr(exprbuf, &eval, &eattr, &esym) != OK)
 531                                 goto loop;
 532                 }
 533                 //equ a equr
 534                 else if (*tok == SYMBOL)
 535                 {
 536                         sy2 = lookup(string[tok[1]], LABEL, j);
 537
 538                         if (sy2 && (sy2->sattre & EQUATEDREG))
 539                         {
 540                                 sy->stype = sy2->stype;
 541                                 sy->sattr = sy2->sattr;
 542                                 sy->sattre = sy2->sattre;
 543 //ICK                           sy->svalue = (sy2->svalue & 0xFFFFF0FF);
 544                                 sy->svalue = sy2->svalue;
 545                                 goto loop;
 546                         }
 547                         else if (expr(exprbuf, &eval, &eattr, &esym) != OK)
 548                                 goto loop;
 549                 }
 550                 else if (expr(exprbuf, &eval, &eattr, &esym) != OK)
 551                         goto loop;
 552
 553                 if (!(eattr & DEFINED))
 554                 {
 555                         error(undef_error);
 556                         goto loop;
 557                 }
 558
 559                 sy->sattr |= eattr | EQUATED;           // Symbol inherits value and attributes
 560                 sy->svalue = eval;
 561
 562                 if (list_flag)                                          // Put value in listing
 563                         listvalue(eval);
 564
 565                 at_eol();                                                       // Must be at EOL now
 566                 goto loop;
 567         }
 568
 569         // Do labels
 570         if (label != NULL)
 571         {
 572 do_label:
 573                 // Check for dot in front of label; means this is a local label if present
 574                 j = (*label == '.' ? curenv : 0);
 575                 sy = lookup(label, LABEL, j);
 576
 577                 if (sy == NULL)
 578                 {
 579                         sy = NewSymbol(label, LABEL, j);
 580                         sy->sattr = 0;
 581                         sy->sattre = RISCSYM;
 582                 }
 583                 else if (sy->sattr & DEFINED)
 584                 {
 585                         errors("multiply-defined label '%s'", label);
 586                         goto loop;
 587                 }
 588
 589                 // Put symbol in "order of definition" list
 590                 if (!(sy->sattr & SDECLLIST))
 591                         sym_decl(sy);
 592
 593                 if (orgactive)
 594                 {
 595                         sy->svalue = orgaddr;
 596                         sy->sattr |= ABS | DEFINED | EQUATED;
 597                 }
 598                 else
 599                 {
 600                         sy->svalue = sloc;
 601                         sy->sattr |= DEFINED | cursect;
 602                 }
 603
 604                 lab_sym = sy;
 605
 606                 if (!j)
 607                         curenv++;
 608
 609                 // Make label global
 610                 if (labtyp == DCOLON)
 611                 {
 612                         if (j)
 613                         {
 614                                 error(locgl_error);
 615                                 goto loop;
 616                         }
 617
 618                         sy->sattr |= GLOBAL;
 619                 }
 620
 621                 // If we're in as68 mode, and there's another label, go back and handle it
 622                 if (as68_flag && as68mode)
 623                         goto as68label;
 624         }
 625
 626         // Punt on EOL
 627         if (state == -3)
 628                 goto loop;
 629
 630         // If we are in GPU or DSP mode and still in need of a mnemonic then search
 631         // for one
 632         if ((rgpu || rdsp) && (state < 0 || state >= 1000))
 633         {
 634                 for(state=0, p=opname; state>=0;)
 635                 {
 636                         j = mrbase[state] + (int)tolowertab[*p];
 637
 638                         // Reject, character doesn't match
 639                         if (mrcheck[j] != state)
 640                         {
 641                                 state = -1;                                     // No match
 642                                 break;
 643                         }
 644
 645                         // Must accept or reject at EOS
 646                         if (!*++p)
 647                         {
 648                                 state = mraccept[j];            // (-1 on no terminal match)
 649                                 break;
 650                         }
 651
 652                         state = mrtab[j];
 653                 }
 654
 655                 // Call RISC code generator if we found a mnemonic
 656                 if (state >= 3000)
 657                 {
 658                         GenerateRISCCode(state);
 659                         goto loop;
 660                 }
 661         }
 662
 663         // Invoke macro or complain about bad mnemonic
 664         if (state < 0)
 665         {
 666                 if ((sy = lookup(opname, MACRO, 0)) != NULL)
 667                         InvokeMacro(sy, siz);
 668                 else
 669                         errors("unknown op '%s'", opname);
 670
 671                 goto loop;
 672         }
 673
 674         // Call directive handlers
 675         if (state < 500)
 676         {
 677                 (*dirtab[state])(siz);
 678                 goto loop;
 679         }
 680
 681         // Do mnemonics
 682         // o  can't deposit instrs in BSS or ABS
 683         // o  do automatic .EVEN for instrs
 684         // o  allocate space for largest possible instr
 685         // o  can't do ".b" operations with an address register
 686         if (scattr & SBSS)
 687         {
 688                 error("cannot initialize non-storage (BSS) section");
 689                 goto loop;
 690         }
 691
 692         if (sloc & 1)                                                   // Automatic .even
 693                 auto_even();
 694
 695         if (challoc - ch_size < 18)                             // Make sure have space in current chunk
 696                 chcheck(0);
 697
 698         m = &machtab[state - 1000];
 699
 700         // Call special-mode handler
 701         if (m->mnattr & CGSPECIAL)
 702         {
 703                 (*m->mnfunc)(m->mninst, siz);
 704                 goto loop;
 705         }
 706
 707         if (amode(1) < 0)                                               // Parse 0, 1 or 2 addr modes
 708                 goto loop;
 709
 710         if (*tok != EOL)
 711                 error(extra_stuff);
 712
 713         amsk0 = amsktab[am0];
 714         amsk1 = amsktab[am1];
 715
 716         // Catch attempts to use ".B" with an address register (yes, this check
 717         // does work at this level)
 718         if (siz == SIZB && (am0 == AREG || am1 == AREG))
 719         {
 720                 error("cannot use '.b' with an address register");
 721                 goto loop;
 722         }
 723
 724         for(;;)
 725         {
 726                 if ((m->mnattr & siz) && (amsk0 & m->mn0) != 0 && (amsk1 & m->mn1) != 0)
 727                 {
 728                         (*m->mnfunc)(m->mninst, siz);
 729                         goto loop;
 730                 }
 731
 732                 m = &machtab[m->mncont];
 733         }
 734 }
 735
 736
 737 //
 738 // .if, Start Conditional Assembly
 739 //
 740 int d_if(void)
 741 {
 742         IFENT * rif;
 743         WORD eattr;
 744         VALUE eval;
 745         SYM * esym;
 746
 747         // Alloc an IFENTRY
 748         if ((rif = f_ifent) == NULL)
 749                 rif = (IFENT *)malloc(sizeof(IFENT));
 750         else
 751                 f_ifent = rif->if_prev;
 752
 753         rif->if_prev = ifent;
 754         ifent = rif;
 755
 756         if (!disabled)
 757         {
 758                 if (expr(exprbuf, &eval, &eattr, &esym) != OK)
 759                         return 0;
 760
 761                 if ((eattr & DEFINED) == 0)
 762                         return error(undef_error);
 763
 764                 disabled = !eval;
 765         }
 766
 767         rif->if_state = (WORD)disabled;
 768         return 0;
 769 }
 770
 771
 772 //
 773 // .else, Do Alternate Case For .if
 774 //
 775 int d_else(void)
 776 {
 777         IFENT * rif = ifent;
 778
 779         if (rif->if_prev == NULL)
 780                 return error("mismatched .else");
 781
 782         if (disabled)
 783                 disabled = rif->if_prev->if_state;
 784         else
 785                 disabled = 1;
 786
 787         rif->if_state = (WORD)disabled;
 788         return 0;
 789 }
 790
 791
 792 //
 793 // .endif, End of conditional assembly block
 794 // This is also called by fpop() to pop levels of IFENTs in case a macro or
 795 // include file exits early with `exitm' or `end'.
 796 //
 797 int d_endif (void)
 798 {
 799         IFENT * rif = ifent;
 800
 801         if (rif->if_prev == NULL)
 802                 return error("mismatched .endif");
 803
 804         ifent = rif->if_prev;
 805         disabled = rif->if_prev->if_state;
 806         rif->if_prev = f_ifent;
 807         f_ifent = rif;
 808         return 0;
 809 }